1. Field of the Invention
The present invention relates to an image forming apparatus including a detection unit that detects an overcurrent.
2. Description of the Related Art
An image processing apparatus (image forming apparatus) which stops supplying power to a printer unit to reduce standby power consumption during standby in which a printing function is not executed (Japanese Patent Application Laid-Open No. 2001-109546), is known. The image processing apparatus discussed in Japanese Patent Application Laid-Open No. 2001-109546 includes a slave CPU, to which a first power supply unit supplies power regardless of a state (an on/off state) of a power switch operated by a user. The image processing apparatus also includes a master CPU, to which a second power supply unit supplies power when the power switch is on. In addition to the master CPU, the second power supply unit also supplies power to a copy function control unit that controls a copy function of the image processing apparatus.
This image processing apparatus discussed in Japanese Patent Application Laid-Open No. 2001-109546 enables the master CPU to execute turn-off processing, such as data saving processing, when the user turns off the power switch. When the turn-off processing is finished, the master CPU instructs the slave CPU to turn off power to the image processing apparatus. The slave CPU, which has received the instruction, turns off a switch arranged between the commercial power and the second power supply unit. This stops power supply from the grid power to the second power supply unit, stopping power supply to the master CPU and the copy function control unit.
A short circuit, which may be caused by reasons such as a failure of an electronic component to which the second power supply unit supplies power, would lead to passage of an excessive current if the second power supply unit maintains the output voltage. A solution typically provided for such an excessive current passing from the second power supply unit is a mechanism (a protective circuit) to shut off the passage of current from the second power supply unit. The image processing apparatus discussed in Japanese Patent Application Laid-Open No. 2001-109546 shuts off power supply from the second power supply unit by such a protective circuit in a case of a short circuit of an electronic component in the copy function control unit due to reasons such as a failure. This shuts off power supply to the master CPU, to which the second power supply unit supplies power. In other words, this image processing apparatus discussed in Japanese Patent Application Laid-Open No. 2001-109546 shuts off the power supply to the master CPU immediately when an overcurrent flows due to reasons such as a short circuit in an electronic component of a device to which the second power supply unit supplies power. Thus, in this image processing apparatus discussed in Japanese Patent Application Laid-Open No. 2001-109546, power supply to the master CPU is stopped without the master CPU performing the turn-off processing described above. As a result, data prior to the occurrence of the short circuit may be erased without being saved.